1. Field of the Invention
This invention relates to a pearlescent concentrate in the form of a free-flowing aqueous dispersion.
Aqueous compositions of surfactants and cosmetic preparations can be given a pearlescent, aesthetically attractive appearance by incorporation of substances which, after cooling, precipitate in the form of fine, nacreous crystals and remain dispersed in the compositions. Suitable pearlescers include, for example, the monoesters and diesters of ethylene glycol, propylene glycol and oligomeric alkylene glycols of this type or glycerol with C.sub.16 -C.sub.22 fatty acids and also monoalkanolamides of C.sub.12 -C.sub.22 fatty acids with alkanolamines containing 2 or 3 carbon atoms.
It is also known that the pearlescers mentioned above can be stably dispersed in water or in aqueous surfactant solutions and that the concentrated pearlescent dispersions thus obtained may be added without heating to the preparations to be made pearlescent, so that there is no need for the heating and cooling otherwise necessary for incorporation to form the pearlescent crystals.
2. Discussion of Related Art
Pearlescent concentrates based on the pearlescers mentioned above are known, for example, from German patent application No. 16 69 152 and from Japan patent application No. 56/71021 (Chem. Abst. 95/156360). The pearlescent concentrates known from Japan application No. 56/71021 are attended by the disadvantage that they are not free-flowing and do not form stable, free-flowing dispersions on corresponding dilution with water. This makes the concentrates very difficult to handle and process on an industrial scale. The pearlescent concentrates known from German application No. 16 69 152 contain anionic surfactants to stabilize the dispersion in its liquid state. These concentrates have the disadvantage that, in formulations containing constituents of opposite ionicity, they are incompatible and impair the stability of the dispersion or, in fommulations containing cationic conditioning constituents, lead to a reduction in the conditioning effect. It has been found that many nonionic and zwitterionic emulsifiers lead either to pearlescent dispersions of low stability and brilliance or to pearlescent dispersions which, in cationic hair-care formulations, reduce the effect of the cationic conditioning constituents. Accordingly, an object of the present invention is to provide emulsifiers with which it is possible to prepare free-flowing pearlescent dispersions combining high brilliance and high stability with high compatibility with cationic conditioning components.